This invention relates generally to fiber-optic bundles, and more particularly to the passage of fiber-optic bundles through walls or other physical structures while maintaining the environmental conditions within the wall or structure.
The collection and measurement of light emitted from various sources can be achieved through the use of fiber-optic technology. For example, various kinds of light, such as visible light, infrared, ultraviolet, and flourescent light are transmissible through optical fiber. Extensive work to improve this technology continues because of the increasing importance of light transmission in communications and in various scientific endeavors.
Light sources are often enclosed in controlled environments using chambers capable of creating a variety of pressure and temperature conditions. The fiber optics must therefore pass through a wall of the chamber while allowing the chamber to maintain the desired environmental conditions. A hermetic seal at this feedthrough allows the chamber to maintain this condition.
In the past, fiber-optic bulkhead feedthroughs have been developed employing metallic film optical fiber protection and a compression method of assembly to hermetically seal the plurality of fibers within the feedthrough housing. Another feedthrough module includes a housing and one or a plurality of fibers each fed through a separate hole in the housing with a sealing material used to hermetically seal the fibers in the holes.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
The present invention provides a method and apparatus for hermetically sealing fiber-optic bundles passing through a wall or other structure. The invention allows environmental conditions (e.g., pressure, temperature, moisture, etc.) to be maintained within a chamber or enclosure into which a fiber-optic bundle extends. One embodiment of the invention comprises a rigid sleeve, a flange for attaching the sleeve to a wall, a bundle of optical fibers, and a resin-derived solid polymer sealant intimately bonded to each of the optical fibers in the bundle and to an inner surface of the sleeve. Preferably, the resin-derived solid polymer sealant is derived from an epoxy resin.
The hermetically sealed fiber-optic bundle feedthrough can be used to transmit an optical signal, many optical signals, an optical image, or many optical images from one environment to another environment where the two environments are separated by a sealing material that can sustain high fluid or gas pressure differentials and/or high temperature differentials. The optical fibers that extend into either environment are flexible and can be arranged to collect and deliver light in a multitude of configurations. The hermetically sealed fiber-optic bundle feedthrough can be used wherever a large amount of optical information needs to be transmitted from one environment to another.
One embodiment of the present invention provides a sealed feedthrough for a barrier. The feedthrough includes a sleeve assembly, a fiber-optic bundle, and a sealing material. The sleeve assembly is disposed adjacent the opening in the barrier and is sealed to the barrier. The sleeve assembly includes a sleeve having two ends and an interior surface defining an opening between the two ends. The fiber-optic bundle extends into the opening of the sleeve and includes a plurality of optical fibers. The sealing material is disposed within the opening of the sleeve, between the optical fibers, and between the bundle and the interior surface of the sleeve, thereby creating a seal between the two ends of the sleeve.
In one embodiment of the feedthrough, the sleeve assembly includes a flange to seal the sleeve to the barrier.
In another embodiment of the feedthrough, the flange includes a base portion, a tube portion, and a means for sealing the tube portion to the sleeve.
In yet another embodiment of the feedthrough, a compression O-ring seal is disposed between the flange and the barrier. In this or other embodiments, a compression O-ring seal may also be disposed between the flange and the sleeve.
In certain embodiments of the feedthrough, the fiber-optic bundle includes between 100 and 100,000 optical fibers, but it is envisioned that more than 100,000 optical fibers could be included in the fiber-optic bundle. In one particular embodiment, the fiber-optic bundle includes approximately 70,000 optical fibers.
In yet another embodiment of the feedthrough, the optical fibers are separated from each other by the sealing material providing additional optical isolation.
In certain embodiments of the feedthrough, a sealing flange is attached to the outside of the sleeve. The flange includes a first compression O-ring for sealing to the sleeve and a second compression O-ring for sealing to the barrier. In other embodiments, the sleeve includes an integrally formed flange.
In certain embodiments of the feedthrough, the sealing material is an epoxy resin.
The present invention further relates to methods of manufacturing hermetically sealed bundle feedthroughs. One such method includes the steps of providing a rigid sleeve, placing a fiber-optic bundle having a plurality of optical fibers through the sleeve, coating the fibers immediately adjacent to one end of the sleeve with a sealing material, pulling the fibers coated with sealing material into the sleeve, and curing the sealing material.
Another method provides the additional step of combing the fiber-optic bundle to separate the optical fibers.
Yet another method provides the additional step of wrapping an end of the optical bundle with tape.
Yet still another method provides the additional step of attaching a flange to an exterior surface of the sleeve. In this method, the attaching step may include the steps of placing an O-ring on the sleeve and compressing the O-ring with the sealing flange, thereby sealing the sleeve to the sealing flange.